Interface unit



FIG. 1 is an isometric view of an interface unit showing my new design;

FIG. 2 is a front elevation view thereof.

FIG. 3 is a left side elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is bottom top plan view thereof. 

The ornamental design for an interface unit, as shown and described. 